/Engine/Source/Runtime/GeometryCore/Public/Util/IteratorUtil.h
This is done via the PairExpandFunctionTTFunction, which returns aFIndex2ifor a given integer. This pair must be either (a,invalid), (a, b), or (invalid, invalid), where invalid is integer < 0
template<typename InputIteratorT> class TPairExpandIterator
InputIteratorT
Cur
FIndex2i
CurPair
int
CurPairI
int
CurValue
InputIteratorT
End
PairExpandFunct...
PairFunc